On Tue, Jan 26, 2021 at 11:00:11AM +0200, Baruch Siach wrote:

commit e73b0101ae5124bf7cd3fb5d250302ad2f16a416 upstream.

The period is the sum of on and off values. That is, calculate period as

($on + $off) / clkrate

instead of

$off / clkrate - $on / clkrate

that makes no sense.

Reported-by: Russell King linux@armlinux.org.uk Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Fixes: 757642f9a584e ("gpio: mvebu: Add limited PWM support") Signed-off-by: Baruch Siach baruch@tkos.co.il Signed-off-by: Bartosz Golaszewski bgolaszewski@baylibre.com

Doesn't this need something like:

[baruch: Backported to 5.10]

plus a new S-o-B?

---

This backported patch applies to all kernels between 4.14 and 5.10 (inclusive).

---

drivers/gpio/gpio-mvebu.c | 25 ++++++++++--------------- 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/gpio/gpio-mvebu.c b/drivers/gpio/gpio-mvebu.c index 2f245594a90a..ed7c5fc47f52 100644 --- a/drivers/gpio/gpio-mvebu.c +++ b/drivers/gpio/gpio-mvebu.c @@ -660,9 +660,8 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip, spin_lock_irqsave(&mvpwm->lock, flags);

• val = (unsigned long long)

• readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
  

• val *= NSEC_PER_SEC;

• u = readl_relaxed(mvebu_pwmreg_blink_on_duration(mvpwm));
• val = (unsigned long long) u * NSEC_PER_SEC; do_div(val, mvpwm->clk_rate); if (val > UINT_MAX) state->duty_cycle = UINT_MAX;

@@ -671,21 +670,17 @@ static void mvebu_pwm_get_state(struct pwm_chip *chip, else state->duty_cycle = 1;

• val = (unsigned long long)

• readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm));
  

• val = (unsigned long long) u; /* on duration */
• /* period = on + off duration */
• val += readl_relaxed(mvebu_pwmreg_blink_off_duration(mvpwm)); val *= NSEC_PER_SEC; do_div(val, mvpwm->clk_rate);

• if (val < state->duty_cycle) {

• if (val > UINT_MAX)

• state->period = UINT_MAX;
  

• else if (val)

• state->period = val;
  

• else state->period = 1;

• } else {

• val -= state->duty_cycle;
  

• if (val > UINT_MAX)
  

• 	state->period = UINT_MAX;
  

• else if (val)
  

• 	state->period = val;
  

• else
  

• 	state->period = 1;
  

• }

regmap_read(mvchip->regs, GPIO_BLINK_EN_OFF + mvchip->offset, &u); if (u)

Reviewed-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de

Thanks Uwe